Mary Russell, an attorney who founded Stock Option Counsel to help employees evaluate their equity compensation, says the first step is for employees to make sure any equity is theirs to keep. Some companies have repurchase rights in their equity agreements that give them a right to buy back shares and options from any employee who leaves; and some give founders or investors broad latitude to change the terms.

“If the company can take back employee shares it dramatically limits the value of those shares,” says Ms. Russell. “It’s the sort of thing an employee needs to know about when they go into a job.” She says it’s as simple as asking whether the company can take back vested shares.